This may sound really stupid but, since installing my z1 almost a year ago i have never tried to turn it off when in my vehicle. Where the heck is the on/off button?" lol. I would appreciate the help

It's never "OFF" It boots up when you start the vehicle and shuts off when the vehicle is off. You can turn the sound off, but they assume the nav system will want to be on 24/7 when your car is on. That and the slow boot up times is probably why the unit is on when the car is on.

You can turn off the display though. Hold the "v" button until the screen blanks.

and if you press and hold the AV button, you can put it into a "sleep" mode, where it doesn't play anything. I've been using this function instead of the missing mute button.

and if you press and hold the AV button, you can put it into a "sleep" mode, where it doesn't play anything. I've been using this function instead of the missing mute button.

Does the Nav still work? How do you get it out of the "sleep" mode?

Thank you!

Steve

PS: A mute button would be a good thing

Yes the navi still works. Touching AV again will go back to whatever source you were on. And holding the down the AV button is essentially a mute button except for the navi voice. If you use it during a song, movie, or on your ipod, it will return to the same spot when you touch it again. I agree an on-screen mute button like the D3 would be nice though